The present invention relates to a three-dimensional simulator apparatus and an image synthesis method capable of simulating a virtual three-dimensional (3D) space.
Various types of three-dimensional (3D) simulator apparatus that are used in applications such as 3D games and piloting simulators for aircraft or other vehicles are known in the art. With such a 3D simulator apparatus, image information relating to a 3D object 300 shown in FIG. 20A is previously stored within the apparatus. This 3D object 300 depicts an element such as scenery that can be seen by a player (observer) 302 as if through a screen 306. This display object is displayed as a pseudo-3D image (projected image) 308 on the screen 306, by perspective projection conversion on the screen 306 of the image information of the 3D object 300. When the player 302 specifies an operation such as rotation or forward motion through a control panel 304, this apparatus performs predetermined 3D computation processing on the basis of the resultant operating signals. More specifically, computations are first performed to determine whether a change has occurred, such as a change in the viewpoint and where the eyes of the player 302 are directed or a change in the position and orientation of a vehicle in which the player 302 is sitting, as specified by these operating signals. Computations are then performed to determine how the image of the 3D object 300 can be seen on the screen 306, in accordance with this change such as a change in viewpoint and where the player""s eyes are directed. The above computations are performed in real time, following the actions of the player 302. This makes it possible for the player 302 to see any change in the scenery, due to a change in the player""s own viewpoint or where the player""s eyes are directed or a change in the position or orientation of the vehicle in which the player is sitting, as a pseudo-3D image in real time, to simulate the experience of a virtual 3D space.
An example of a displayed image formed by a 3D simulator apparatus as described above is shown in FIG. 20B.
In a 3D simulator apparatus of this type, each display object is represented by assembling a large number of polygons. Taking a tire in a racing car game by way of example, each of a side surface and a running surface of the tire is configured of an assembly of a plurality of polygons. A method called texture mapping is also used, to increase the quality of the image to be displayed. This texture mapping method applies a texture onto a polygon configuring the display object to achieve a more realistic displayed image. With this tire as an example, a texture that represents lettering and a wheel (spoke) pattern is mapped onto the side surface of the tire. Similarly, a texture that represents the tread surface of the tire is mapped onto the running surface thereof. In the prior art, only one type of texture can be provided for each display object.
However, a problem occurs with the example of mapping the texture of lettering on the side surface of a tire, as described below. That is, in the real world simulated by this 3D simulator apparatus, the lettering ought to flow in the direction of rotation of the tire as the tire rotates, and the outlines of this lettering ought to start to blur as the rotation increases. Even if the 3D simulator apparatus were to attempt to simulate this phenomenon, however, it has been shown that the outlines of the lettering will not blur. The reason for this relates to the processing speed of the 3D simulator apparatus and is caused by the fact that an image is generated once every {fraction (1/60)} second, for example, unlike in the real world. Therefore, there is a problem that it is not possible to realistically simulate the blurring of the outlines of the lettering that would occur in the real world, by simply applying the texture of lettering to the side surface of the tire and rotating the tire at high speed.
A further problem occurs with the example of mapping the texture of a tread surface onto the running surface of the tire, as described below. In other words, if a racing car should leave the course and run onto another surface such as a gravel road, because of a driving error, gravel or sand would adhere to the running surface of the tire in the real world and the state of the running surface of the tire ought to change accordingly. With a prior-art 3D simulator apparatus, however, only one texture can be provided for each display object. This causes a problem in that it is not possible to represent such a change in the state of the running surface of the tire, and thus a phenomenon that occurs in the real world cannot be simulated realistically.
The present invention has been devised in the light of the above described technical problems and has as its objective the provision of a 3D simulator apparatus and an image synthesis method that can simulate the real world realistically, even when the velocity and/or rotational velocity of a display object has changed.
Another objective of the present invention is to provide a 3D simulator apparatus and an image synthesis method that can simulate the real world realistically, even when the surface state of a display object is to change in accordance with simulation circumstances.
In order to solve the above described problems, a first aspect of the present invention concerns a three-dimensional simulator apparatus for synthesizing a field-of-view image as seen from an observer within a virtual three-dimensional (3D) space configured of a plurality of display objects, comprising:
texture computation means for performing computations to map textures onto the display objects;
texture information storage means for storing information of the textures to be mapped by the texture computation means, the texture information storage means for storing different types of texture information corresponding to the same display object; and
modification means for modifying one of the type of information of at least one texture to be mapped onto at least one display object, and information specifying the type, in accordance with at least one of the velocity and rotational velocity of the at least one display object.
With this aspect of the invention, a plurality of types of texture information is stored for mapping onto a display object, such as a side surface of a tire. For example, texture information for a halted state and texture information for high-speed rotational state (or high-speed running state) are stored. Either the type of texture information for the mapping onto the side surface of the tire, or information specifying the type, is changed in a manner consistent with a factor such as the rotational velocity of the tire. Thus lettering with clear outlines can be represented on the side surface tire when the tire is in a halted state, and lettering with blurred outlines can be represented thereon when the tire is in a high-speed rotational state. In this case, the means for modifying the type of texture information may be included within means for forming the virtual 3D space, for example, or means for sythesizing the field-of-view image. Alternatively, such means may be provided separately in both places. This invention includes a configuration in which the type of the texture information is changed in accordance with the relative velocity or relative rotational velocity between the obsever and the display object.
A second aspect of the present invention concerns a three-dimensional simulator apparatus, comprising: means for storing object information that comprises at least object numbers and position information for display objects configuring a virtual three-dimensional (3D) space; virtual 3D space computation means for forming the virtual 3D space by setting the object information; object image information storage means for storing image information of objects specified by the object number; and image synthesis means for synthesizing a field-of-view image as seen from an observer based on the object information and the image information read out in accordance with the object numbers included in the object information;
wherein the image synthesis means comprises:
texture computation means for performing computations to map textures onto the display objects, and texture information storage means for storing information of the textures to be mapped by the texture computation means, the texture information storage means for storing different types of texture information corresponding to the same display object;
the virtual 3D space computation means comprises:
modification means for modifying at least one object number in accordance with at least one of the velocity and rotational velocity of at least one display object specified by the at least one object number; and
the object image information storage means stores the image information wherein information of a texture to be mapped onto an object that is specified by a pre-modification object number is different from information of a texture to be mapped onto an object that is specified by a post-modification object number.
With this aspect of the invention, an object number used for specifying a display object such as a tire object is changed in a manner consistent with a factor such as the rotational velocity of the tire. The object number is changed in such a manner that a tire object for a halted state is specified when the tire is in a halted state, and a tire object for a high-speed rotational state is specified when the tire is rotating at high speed. Corresponding image information of the object is read from the object image information storage means in accordance with the thus changed object number. In this case, the configuration is such that image information for a tire object in the halted state reads out texture information for the halted state, and image information for the tire object in a high-speed rotational state reads out texture information for the high-speed rotational state. This makes it possible to change the texture coordinates (information specifying texture information) within the image information.
In a third aspect of the present invention, the modification means performs the modification in steps in accordance with at least one of the velocity and rotational velocity of the at least one display object.
With this aspect of the invention, when the display object is a tire, for example, the information of the textures to be mapped can be changed in steps to include not only textures for a halted state and a high-speed rotational state, but also for a low-speed rotational state and an intermediate-speed rotational state.
A fourth aspect of the present invention concerns a three-dimensional simulator apparatus for synthesizing a field-of-view image as seen from an observer within a virtual three-dimensional (3D) space configured of a plurality of display objects, comprising:
texture computation means for performing computations to map textures onto the display objects;
texture information storage means for storing information of the textures to be mapped by the texture computation means, the texture information storage means for storing different types of texture information corresponding to the same display object; and
modification means for modifying one of the type of information of at least one texture to be mapped onto at least one display object, and information specifying the type, in accordance with a surface state of the at least one display object, the surface state being changed with simulation circumstances.
With this aspect of the invention, a plurality of types of texture information is stored for mapping onto a display object, such as the running surface of a tire. Texture information for an ordinary road surface and that for a gravel road area may be stored, for example. Either the type of information of the texture to be mapped onto the running surface of the tire or information specifying that type can be changed in a manner consistent with a factor such as the running speed of the racing car. This makes it possible to use a normal state to represent the running surface of the tire when the racing car is running along an ordinary road surface, and a state in which gravel or sand is adhering to the running surface of the tire when the racing car has entered a gravel road area. The means for modifying the type of texture information can be located anywhere within the apparatus in this case.
A fifth aspect of the present invention concerns a three-dimensional simulator apparatus, comprising: means for storing object information that comprises at least object numbers and position information for display objects configuring a virtual three-dimensional (3D) space; virtual 3D space computation means for forming said virtual 3D space by setting the object information; object image information storage means for storing image information of objects specified by the object numbers; and image synthesis means for synthesizing a field-of-view image as seen from an observer based on the object information and the image information read out in accordance with the object numbers included in the object information;
wherein the image synthesis means comprises:
texture computation means for performing computations to map textures onto said display objects; texture information storage means for storing information of the textures to be mapped by the texture computation means, the texture information storage means for storing different types of texture information corresponding to the same display object;
the virtual 3D space computation means comprises:
modification means for modifying at least one object number in accordance with a surface state of at least one display object specified by the at least one object number, the surface state being changed with simulation circumstances; and
the object image information storage means stores the image information wherein information of a texture to be mapped onto an object that is specified by a pre-modification object number is different from information of a texture to be mapped onto an object that is specified by a post-modification object number.
With this aspect of the invention, the object number used for specifying the tire object can be changed in a manner consistent with a change in a display object, such as the surface of the tire, caused by the circumstances of the simulation. The object number may be changed to specify that a tire object corresponding to travel along an ordinary road surface is specified when the racing car is running along an ordinary road surface, and a tire object corresponding to travel along a gravel road area is specified when running along a gravel road area, for example. The corresponding image information of the object is read out from the object image information storage means in accordance with the changed object number. In this case, the configuration is such that texture information representing an ordinary tread surface is read out as image information for the tire object for running along the ordinary road surface, and texture information representing a tread surface to which gravel or sand is adhering is read out as image information for the tire object for running along the gravel road area.
In a sixth aspect of the present invention, the modification means performs the modification in steps in accordance with a surface state of the at least one display object.
With this aspect of the invention, if the display object is a tire, for example, the type of texture information onto the display object can be changed in steps in a manner consistent with a factor such as the distance travelled along the gravel road area. This makes it possible to represent a state in which more gravel and sand adheres to the tire as the distance traveled increases.